A fast transient response power supply is needed for many electronic devices. For example, the RF (Radio Frequency) Power Amplifier in a mobile phone has a load profile which includes a burst of high current followed by a quiet period and if powered directly from a battery, the battery supply voltage because of its internal resistance ESR (equivalent series resistance) exhibits a voltage dip (drop) during the bursts of high current. The resulting voltage may not be high enough to power the RF power amplifier. This presents a technical problem for which a technical solution using a technical means is needed.